The complexity of the rf admittance level switches

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using the technology of the rf admittance, rf admittance level switch in absorbing the foreign similar products of advanced technology and function on the basis of the design level control instrument production. Consists of two parts, electronic circuit and the probe, electronic circuit, detection circuit, output circuit, including high frequency oscillator detector consists of detecting great and cases, and between them and insulation between grounding container, provided by the high frequency oscillator stability of rf voltage, to probe on the great, when material detection great touches, unbalanced output voltage, by modem, amplifier, drive the relay action. So-called rf admittance, the meaning of the admittance to the reciprocal of electrical impedance in, its element by resistive, capacitive component, the perceptual component integrated, and radio frequency or high frequency radio spectrum, so the radio frequency admittance can be understood as admittance is measured with a high frequency radio waves. Instrument, instrument of the sensor and filling walls and forming admittance values measured medium, level changes, admittance values change accordingly, circuit unit convert measurement admittance values into material level signal output, to achieve material level measurement.

level itself to probe is equivalent to a capacitor, it does not consume the energy of the transmitter, Pure capacitance energy) 。 But hanging of probe equivalent circuit containing resistors, the impedance of the hanging will consume energy, thus the generator voltage, output change lead to bridge road, measurement error is produced. Between oscillator and bridge added a buffer amplifier, to supplement energy, so that it can't be reduce plus oscillating voltage in the probe. With conductive medium under test, probe insulating layer on the surface of the ground cover the whole and hanging area measured medium, make effective measuring capacitance extend to the top of the hanging. So hanging error occurs, and electrical conductivity stronger, the greater the error. But any measured medium is not completely conductive.

rf admittance level switches can be widely used in metallurgical, chemical, oil, electricity, food, paper making, coal, building materials, medicine and other fields of material level, liquid level alarm and control, and PLC or DCS collecting and distributing control system with PLC, realize the automatic control of production process and the automatic detection.